Railway signaling



A ril 11, 1939. R. R. KEMMERER RAILWAY SIGNALING Filed Sept 29, 1938 5 Sheets-Sheet l INVENTQR I wmm HIS ATTORNEY April 1 1, 1939. R. R. KEMMERER RAILWAY S I GNALI NG iled Sept. 29, 1 958 3 Sheets-Sheet 2 NV NTOR I lziflmenep. v ATTORNEY April 11, 1939. R. R. KEMMERER RAILWAY S IGNALING Filed Sept. 29, 1958 3 Sheets-Sheet 3 INVENTOR 1262401222 mmereh HIS ATTORNEY Patented Apr. 11, 1939 A UNITED STATES PATENT OFFICE RAILWAY SIGNALING Application September 29, 1938, Serial No. 232,384

13 Claims.

My invention relates to railway signaling, and particularly to apparatus for controlling wayside signals by coded and steady currents carried by a pair of line conductors between succeeding sig- 5 nal locations.

I shall describe three forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1a and 1b,

10 when placed end to end with Fig. 111 on the left, constitute a diagrammatic view showing one form of apparatus embodying my invention for the control of five block automatic color light signals; Fig. 2 is a diagrammatic view, showing 35 a modification of the apparatus shown adjacent each signal location in Figs. 1a and 111, for the control of three block automatic color light signals; and Fig. 3 is a diagrammatic view showing a modification of the apparatus of Fig. 2 for 20 controlling combined semaphore and color light signals.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1a and 1b, the reference characters 1 and la designate the rails of a stretch of railway track over which traffic normally moves in the direction indicated by the arrow, which I shall assume to be the eastbound direction. Rails 1 and la are divided by insu- 30 lated joints 8 into blocks l|-l2,- l2-- l3, |3I4,

|4-|5, and l5-I6.

Each of these blocks as shown is further divided by other insulated joints 8 into two sections, block l|l2, for example, being divided into sections |l-l la and Ha- |2. It is not necessary, for the purpose of my invention, that the blocks be divided as shown. In some instances it might be satisfactory to have only one section for each block, and in other instances it might be necessary to divide each block into more than two sections. Each track section is provided with a track circuit comprising a battery 9 connected across the rails adjacent one end of the section, and a relay, designated by the reference character TR with a distinguishing prefix, connected across the rails adjacent the opposite end of the section.

Adjacent the entrance end of each of the blocks which are shown complete, and also adja- 50 cent the entrance end of the block to the right of point It shown'in part in Fig. b, a signal is located for governing eastbound traific movements. These signals are designated by the reference numerals l, 2, 3, 4, and 6, respectively. 55 It is here assumed that each of the signals is of the color light type comprising an upper group of lamps designated by the reference character A, a middle group of lamps designated by the reference character B, and a lower group of lamps designated by the reference character C. 5 Each upper group of lamps comprises a green lamp G, a yellow lamp Y, and a red lamp R; and each middle group and each lower group of lamps comprises a green lamp G and a red lamp R. It is to be understood, however, that my in- 10 vention is not limited to signals of this particular type.

The lighting of the lamps of each of the signals l-6, inclusive, is controlled by a polarized signal control relay having a slow release neutral armature, designated by the reference character HD with a numerical prefix corresponding to the reference numeral for its signal, and by two slow release repeater relays designated by the reference characters ADP and BDP, respectively, with a prefix corresponding to the reference character for the associated signal. The slow release repeater relays ADP and BDP are controlled by front contacts of normal and reverse slow release decoding relays designated'by the reference char- 5 acters AD and BD, respectively, with numerical prefixes corresponding to the reference character of the associated signal.

, Each normal decoding relay AD is controlled by a normal decoding transformer designated by 0 the reference character AT with a prefix corresponding to the reference character for the associated signal, and by normal contacts of a polarized code following relay designated by the reference character CP with a prefix corresponding to the reference character for the associated signal. Each reverse decoding relay BD is controlled by a reverse decoding transformer designated by the reference character BT with a prefix corresponding to the reference character for 40 the associated signal, and by reverse contacts of the polarized code following relay GP for the associated signal.

Each normal decoding transformer AT is controlled by normal contacts of the code following relay GP for the associated signal, and each reverse decoding transformer BT is controlled by reverse contacts of the associated code following relay CP.

Each code following relay CP is responsive to current of a given polarity, which I shall call normal polarity, for closing its contacts l1 and 20, which I have called normal contacts, in the inclined left-hand position as shown in the drawings, which I shall call the normal position. Each 5 code following relay CP is also responsive to current of the opposite or reverse polarity for closing its contacts 2| and 24, which I have called reverse contacts, in the inclined right-hand position as shown in the drawings, which I shall call the reverse position.

The contacts I! and 20 become closed in the vertical position, which I shall call the deenergized position, when the correspondingrelay CP becomes deenergized, and remain closed in that position when the corresponding CP relay becomes energized by current of reverse polarity. The contacts 2| and 24 similarly become closed in the vertical position when the corresponding relay CP becomes deenergized, and remain closed in that position when their GP relay becomes energized by current of normal polarity.

Each relay CP is energized by current carried over a pair of conductors 35 and 42 between the associated signal and the next signal in advance, and controlled by the track relays TR for the block of the associated signal and by the slow releaserepeater' relays and polarized signal controlrelay for the next signal in advance and also by a coding device designated by the reference character CT with a prefix corresponding to the reference character for the next signal in ad- Vance.

Each polarized signal control relay HD is controlled over the same contacts as the code following relayCP forthe same signal, and is alsocontrolled by back contacts of the decoding relays AD and ED for the same signal.

Each coding device CT is constantly connected to the terminals 11 and o of a source of current not shown in the drawings, which can be of any suitable form, but which is here assumed to be a source of constant direct current. The coding devices C'I operate to open and close their contacts at any suitable frequency such, for example, as 180 cycles per minute.

As shown in Fig. 1b, the track section immediately in advance of signal I is occupied by a train W. The indication displayed by each of the signals I to,6, inclusive, under this condition, and

the meaningsof these indications are stated in the following table:

I shall now describe the manner in which these indications are displayed when a train W is in the section immediately ahead of signal Under this condition, relay ITR is deenergized, and hence the circuits for controlling relay ICP, only a portion of which is shown, are open at contacts 36 and 4| of relay lTR. The circuits for relay II-ID are also open at these same contacts. Relay ICP being deenergized, relays IAD and IBD controlled by transformers. IAT and |BT, respectively, and by relay ICP will be deenergized, and

relays ADP and IBDP controlled by relays IAD and IBD, respectively, will also be, deenergized.

Lamp R of the upper group A of signal I is therefore lighted by a circuit passing from terminal 22, through the back points of contacts 25, 2t and 2'? of relays IADP, IBDP and ll-ID, respectively, and lamp R of group A to terminal 0. Lamp R of the middle group B of lamps of signal I is also lighted by a circuit passing from terminal 2), through the back points of contacts 28 and 29 of relays IADP and lBDP, respectively, and lamp R to terminal 0. Lamp R of the lower group of lamps C of signal is lighted by a circuit passing from terminal I), through the back point of contact 33 of relay lHD, and lamp R to terminal 0.

At this time, relay .ZHD is energized by a circuit passing from terminal 2), through the back points of contacts 3|, 32, and 33 of relays ll-ID, IBDP and EADP, respectively, contact a". of relay a.2TR, conductor 35, contact 36 of relay ZTR, conductor 3?, contacts 33 and B9 or" relays 213D and 2AD, respectively, winding of relay EI-ID, conductor 40, contact ti of relay ZTR, conductor 42, contact 43 of relay aZTR, and the back poitns of contacts til, 65 and it relays lADP, lBDP and lHD, respectively, to terminal 0. It will be noted that code following relay EC? is also energized by the circuit just traced between terminals 1) and o and contacts 36 and 4|, respectively of relay HR, and then including the windings of relay 2GP. Since the current flowing in this circuit is constant direct current of what I shall term reverse polarity, contact E1 of relay 20? is constantly closed in the deenergized position, and contact 2| of relay 2GP is constantly closed in the reverse position. With these contacts I! and 2| constantly closed, there will be no current generatedin the secondary windings of decoding transformers ZAT and 213T, and hence relays 2AD and ZED will remain deenergized. Relays 2AD]? and 2BDP are therefore also deenergized.

With relay 2HD energized and relays ZADP and ZBDP deenergized, the yellow lamp Y of the upper group of lamps A of signal 2 will be lighted by a circuit passing from terminal 13, through the back points of contacts 25 and 26 of relays 2ADP and IZBDP, respectively, the front point of contact 2| of relay ZI-ID, and lamp Y of group A to terminal o Lamp R of the middle group B of lamps of signal 2 is lighted by a circuit which is exactly like the circuit previously traced for lamp R of the middle group of lamps B of signal l. Lamp R of group C of signal 2 is, however, lighted by a circuit which is different from the circuit previously traced for lamp R of group C of signal I. .The circuit for lamp R of group C of signal 2 passes from terminal b, through the front point of contact 351 of relay ZI-ID, contact t! of relay ZHD in the reverse or right-hand position, and lamp- R of group C of signal 2 to terminal 0.

Relay 3HD is energized by steady current of normal polarity in a circuit passing from terminal 13, through contact E8 of relay 2HD closed in the reverse position, front point of contact 46 of relay 2HD, back points of contacts 45 and 44 of relays 2BDP and ZADP, respectively, contact 43 of relay a3TR, conductor 42, contact 4| of relay 3TR, conductor 4P3, winding of relay 3HD, contacts 39 and 38 of relays 3AD and 33D, respectively, conductor 31, contact 36 of relay 3TB, conductor 35, contact as of relay a3TR, back points of contacts 33 and 32 of relays 2ADP and ZBDP, respectively, the front point of contact 3| of relay 2HD, and contact d9 of relay ZHD closed in the right-hand position, to terminal 0. Relay EC? is also energized by steady current of normal polarity by the circuit traced for relay 3HD betweenterminals b and o and contacts 4| and 36,

respectively, of relay 3TB, and then including the windings of relay 3GP. Contacts l1 and 20 of relay 3GP are therefore closed in the lefthand or normal position, and contacts 2| and 24 of relay CP are closed in the deenergized position. Since these contacts are constantly closed, no current is generated in the secondary windings of decoding transformers 3AT and 313T, and hence relays 3AD and 3BD and, in turn, relays 3ADP and 3BDP remain deenergized.

Under these conditions, lamp Y of the top group A of signal 3 is lighted by a circuit which is exactly similar to the circuit previously traced for lamp Y of the top group of lamps A of signal 2. Lamp R of the middle group B of signal 3 is also lighted by a circuit which is exactly similar to the circuit previously traced for lamp R of group B of signal I. Lamp G of the lowest group C of signal 3 is now lighted by a circuit passing from terminal I), through the front point of contact 30 of relay 3HD, contact 41 of relay 3HD closed in the left-hand or normal position, and lamp G of group C of signal 3 to terminal 0.

With relay 3HD energized by current of normal polarity, and with relays 3ADP and 3BDP deenergized, code following relay 4GP is energized by coded current of reverse polarity passing from terminal I), through contact 50 of coding device 301, which is opening and closing at a frequency such for example as 180 cycles per minute, contact 49 of relay 3HD closed in the left-hand position, front point of contact 3| of relay 3HD', back points of contacts 32 and 33 of relays 3BDP and 3ADP, respectively, contact 34 of relay a4'I'R, conductor 35, contact 36 of relay 4TB, windings of relay 4GP, contact 41 of relay 4TB, conductor 42, contact 43 of relay a4TR, back points of con tacts 44 and 45 of relays 3ADP and 3BDP, respectively, front point of contact 46 of relay 3H1), contact 48 of relay 3HD closed in the lefthand position, and contact 5! of coding device 3CT to terminal 0. With code following relay 4GP energized by coded current of reverse polarity, contact I! of this relay will remain constantly closed in the deenergized position, and hence no current will be generated in the secondary winding of transformer 4AT. Relays 4AD and 4ADP will therefore remain. deenergized.

Contacts 2| and 24 of relay 4GP, however, close alternately at the reverse and deenergized positions, causing current to be generated in the secondary winding 23 of decoding transformer 4BT. This is due to current flowing from terminal I), through contact 2| in its reverse position, and the upper half of primary winding 22 of transformer 4BT to terminal 0. alternately with current flowing from terminal 17, through contact 2| closed in the deenergized position, and through the lower portion of primary winding 22 of decoding transformer 4T to terminal 0.

Slow release decoding relay 413D is therefore energized by current flowing from the upper portion of the secondary winding 23 of transformer 4BT, through contact 24 of relay 4CP closed in the right-hand position, and the winding of relay- 4BD to a mid-point of secondary winding 23, alternately with current flowing from the lower portion of secondary winding 23 of transformer 4'BT, through contact 24 of relay 4GP closed in the deenergized position, and the winding of relay 4131) to the mid-point of secondary winding 23. With relay 4BD energized, relay 4HD is deenergized on account of its control circuits being open at a back contact of relay 4BD. Relay 43D being energized, its contact 52 will be closed, causing relay 4BDP to be energized by its circuit passing from terminal I), through contact 52 of relay 43D, and the Winding of relay 4BDP to terminal 0.

With relay 4BDP energized and relay 4ADP deenergized, lamp R of the top group A of signal 4 will be lighted by current passing from terminal I), through the back point of contact 25 of relay 4ADP, front point of contact 25 of relay 4BDP, and lamp R of group A to terminal 0. Lamp G of the middle group B of the lamps of signal 4 is lighted by current passing from terminal I), through the back point of contact 28 of relay 4ADP, front point of contact 29 of relay 4BDP, and lamp G of group B of signal 4 to terminal o. Lamp R of the bottom group C of the lamps of signal 4 is now lighted by a circuit passing from terminal I), through the back point of contact 30 of relay 4I-ID, and lamp R of group C to terminal 0.

With relay 4BDP energized, and relay 4ADP deenergized, relay 5GP will be energized by coded current of normal polarity passing from terminal b, through contact 50 of coding device 4CT, front point of contact 45 of relay 4BDP, back point of contact 44 of relay 4ADP, contact 43 of relay a5'I'R, conductor 42, contact 4| of relay 5TB, windings of relay 5GP, contact 36 of relay 5TB, conductor 35, contact 34 of relay a5TR, back point of contact 33 of relay 4ADP, front point of contact 32 of relay 4BDP, and contact 5! of coding device 4CT to terminal '0. With relay 5GP energized by coded current or normal polarity, contacts l1 and 20 of relay 5GP close alternately in their left-hand and deenergized positions, causing current to be generated in secondary winding l9 of decoding transformer 5AT, which energizes relay BAD. Contacts 2! and 24 of relay 5GP are constantly closed in the deenergized position, and therefore no current is generated in the secondary winding of the transformer BBT, and hence relay BBD remains deenergized. With relay 5AD energized, relay 5HD is deenergized on account of its circuits being open at a back contact of relay 5A1). With relay EAD energized, slow release repeating relay EADP will be energized by a circuit passing from terminal I), through contact 53 of relay SAD, and the winding of relay 5ADP to terminal 0.

With relay 5ADP energized and relay EBDP deenergized, lamp Y of the top group A of the lamps of signal 5 will be energized by a circuit passing from terminal b, through the front point of contact 25 of relay 5ADP, back point of contact 54 of relay EBDP, and lamp Y of group A to terminal 0. Lamp G of middle group B of the lamps of signal 5 is now lighted by a circuit passing from terminal I), through the front point of contact 28 of relay 5ADP, back point of contact 55 of relay EBDP, and lamp G of group B to terminal 0. Lamp R of the bottom group C of the lamps of signal 5. is now lighted by a circuit similar to the circuit previously traced for lamp R of bottom group C of signal I.

With relay 5ADP energized, code following relay 6GP is energized by coded current impulses of normal polarity alternately with coded current impulses of reverse polarity, the coded current of normal polarity passing from terminal 17-, through the front point of contact 56 of coding device 5CT, front point of contact 44 of relay 5ADP, contact 43 of relay aETR, conductor 42, contact 4i of relay GTR, windings of relay 6GP, contact 36 of relay 6TB, conductor 35, contact 34 of relay aBTR, front point of contact 33'of relay SADP, and the front point of contact 51 of coding device 5CT to terminal 0. The circuit by which relay 6GP receives coded current of reverse polarity is the same as the circuit just traced, except that current is supplied to the circuit from terminal b, through the back point of contact 51 of coding device 5CT, and returns to terminal 0 through the back point of contact 56 of coding device 5CT.

With relay 6GP thus energized by coded current impulses of normal polarity alternately with impulses of reverse polarity by the circuit just traced through the front and back points of contacts 56 and 51 of coding device 5CT, contacts IT and 26 will be operated to the left-hand position by the impulses of normal polarity, and will be operated to the deenergized position when each impulse of normal polarity ceases. Contacts 2| and 24 of relay 6GP will be operated to the righthand position by the impulses of reverse polarity supplied to the windings of relay 6GP, and will return to the deenergized position when each impulse of reverse polarity ceases.

Current will therefore be generated in the secondary windings of both decoding transformers BAT and GET, causing both decoding relays GAD and 63D to be energized. The circuit for relay 6I-ID is now open at back contacts of both relays BAD and GED, and relay SHD therefore remains deenergized. With relays 6AD and GED energized, relays 6ADP and 6BDP, respectively, will also be energized.

With both relays GADP and 6BDP energized, lamp G of the top group A of the lamps of signal 6 will be lighted by a circuit passing from terminal b, through the front points of contacts 25 and 54 of relays GADP and 6BDP, respectively, and lamp G to terminal 0. Lamp R of middle group B of the lamps of signal 6 is now lighted by a circuit passing from terminal b, through the front points of contacts 28 and 55 of relays 6ADP and 6BDP, respectively, and lamp R of group B to terminal 0. Lamp R of the bottom group C of the lamps of signal 6 is lighted by a circuit similar to the circuit previously traced for lamp R of group C of signal I.

The code following relay for the next signal in the rear of signal 6 will now be energized, through circuits including front and back points of contacts 56 and 61 of coding device 6CT, by coded impulses of normal polarity alternately with coded impulses of reverse polarity.

Referring now to Fig. 2, a diagrammatic view is here shown of a modified form of each signal shown in Figs. 1a and lb, and of the apparatus for controlling each of these signals for a three block automatic signaling system. As here shown, each signal has only two groups of lamps, the upper group designated by the reference character A, and the lower group designated by the reference character B. Each upper group comprises a green lamp G, a yellow lamp Y, and a red lamp R as in Figs. 1a. and 1b, and each lower group B comprises a green lamp G and a red lamp R.

In view of the showing in Figs. 1a and 1b, and of the foregoing description of the apparatus shown in Figs. la and lb, it is believed that the operation of the three block signaling system can be readily followed with only the one signal location shown in Fig. 2.

As shown in Fig. 2, each signal is controlled by a polarized signal control relay HD, as in Figs. 1a, and lb, and by only one slow release repeating relay, designated by the reference character ADP. The other slow release repeating relay, together with its decoding relay and decoding transformer shown in Figs. la and 1b, are omitted from Fig. 2. The code following relay CP here has only one pair of contacts I! and 26 which are operated similarly to the contacts having the same reference characters in Figs. 1a and 1b. A slow release approach lighting relay designated by the reference character ER is here shown. The other portions of the apparatus, including coding device CT, decoding transformer AT, decoding relay AD, and slow release repeating relay ADP operate as in Figs. 1a and lb.

The indications displayed by each signal in the three block signaling system, such, for example, as signal la. shown in Fig. 2, under various traffic conditions, and the meanings of these indications, are stated in the following table:

fvVith three blocks clear in advance of signal 4a shown in Fig. 2, relay GP for signal 6a will be energized by coded current of normal polarity in a circuit a portion of which is shown adjacent the signal 4a, and the rest of which is exactly similar to the portions shown adjacent 4a. for the relay GP for the next signal in the rear. The circuit by which relay GP for signal 4a is energized, with three blocks clear in advance of signal 4a, therefore passes from terminal b, through the winding of an approach lighting relay ER for the next signal in advance of signal 4a contact 58 operated by a coding device CT for the next signal in advance of signal 40., front point of contact 59 and back point of contact 66 of relays ADP and HD, respectively, for the next signal in advance of signal 4a, contact 43 of relay a lTR for the block of signal 4a, conductor 42, contact 4! of relay lTR, winding of relay CP, contact 36 of relay 4TR, conductor 65, contact 34 of relay a lTR, and back point of contact 6| and front point of contact 62 of relays HD and ADP for the next signal in advance of signal 4a, to terminal 0.

With relay CP thus energized by coded current of normal polarity, its contacts I7 and 20' will be closed alternately in its left-hand and deenergized positions at a frequency corresponding to the frequency at which the coding device CT for the next signal in advance of signal la opens its contact 58. Current will therefore be generated in secondary winding l9 of decoding transformer AT, which will energize decoding relay AD. With decoding relay AD energized, slow release repeater relay ADP will be energized by a circuit passing from terminal b through the front point of contact 53 of relay AD, and the winding of. relay ADP to terminal 0.

With relay ADP energized, lamp G of the upper group A of signal 4a will become lighted, when a train enters the block in the rear of signal 4a, by a circuit passing from terminal b, through contact 63 of relay ER, front point of contact 64 of relay ADP, and lamp G of group A of signal 4a to terminal 0. At the same time, lamp R of group B of, the lamps of signal 4a will become lighted by a circuit passing from terminal b, through contact 63 of relay ER, front point of contact 65 of relay ADP, and lamp R of group B to terminal 0.

When a train passes signal 4a, relay 4TR will become deenergized, thereby opening, at its contacts 36 and 4|, the circuits for relays CP and HD. Relays AD and ADP'will therefore also be deenergized, and lamp R of the upper group A of the lamps of signal lo will then become lighted by a circuit passing from terminal I), through contact 63 of relay ER, back points of contacts 54 and 66 of relays ADP and HD, respectively, and lamp R of signal 4a to terminal 0. At the, same time, lamp R of the lower group of lamps B of signal 4a will become lighted by a circuit passing from terminal b, through contact 63 of relay ER, back points of contacts 55 and 67 of relays ADP and HD, respectively, and lamp R of group B to terminal 0.

When the train clears the block of signal 4a and occupies the second block in advance of signal 4a, relay HD for signal 4a will become energized by steady current of reverse polarity passing from terminal I), through the winding of relay ER for the next signal in advance of signal 4a, back points of contacts 62 and BI of relays ADP and HD, respectively, for the next signal in advance of signal 4a, contact 34 of relay aflTR, conductor 35, contact 36 of relay 4TR, winding of relay HD, contact 39 of relay AD, contact 4| of relay lTR, conductor 42, contact 43 of relay MTR, and the back points of contacts 6!! and and 59 of relays HD and ADP, respectively, for the next signal in advance of signal to, to terminal 0. Relay Cl? for signal la will now be energized by the circuit traced for relay I-ID between terminals h and o and contacts 36 and M, respectively, of relay lTR, and then including the winding of relay CP. With relay CP thus energized by steady current of reverse polarity, contacts El and 25! of relay CP will remain closed in the deenergized position, and hence no current will be generated in the secondary winding of decoding transformer AT for signal 4a. Relays AD and ADP for signal Act will therefore be deenergized.

With relay ADP deenergized and relay HD energized by current of reverse polarity, lamp Y' of upper group A of the lamps of signal 4a, when a train enters the block to the rear of signal 4a, will become lighted by a circuit passing from terminal b, through contact 63 of relay ER, back point of contact 54 of relay ADP, front point of contact 66 of relay HD, and lamp Y of group A of signal 4a to terminal At the same time, lamp R of the lower group B of'the lamps of signal M will become lighted by a circuit passing from terminal I), through contact 63 of relay ER, back point of contact 65 of relay ADP, front point of contact 8'5 of relay HD, contact 69 of relay HD closed in the right-hand or reverse position, and lamp R of group B of signal 4a'to terminal 0.

When the first train clears the first two blocks in advance of signal 4a and occupies the third block in advance of this signal, relay HD for signal 4a will become energized by steady current of normal polarity flowing in a circuit passing from terminal I), through relay ER for the next signal in advance of signal 4a, contact 68 in the reverse position and front point of contact 60, both of relay HD for the next signal in advance of signal la, contact 43 of relay adTR, conductor 42, contact 3! of relay 4TR, contact39 of relay AD, winding of relay I-ID, contact 36 of relay 4TR, conductor 35, contact 34 of relay a4TR,

and front point of contact 6| of relay HD for the next signal in advance of signal 4a to terminal 0. Relay GP for signal 4a will now also be energized by steady current of normal polarity, causing contacts I! and 20 of relay GP to remain closed constantly in their left-hand position. With contacts H and 20 of relay CP constantly closed, no current will be generated in secondary winding it of decoding transformer AT, and hence relays AD and ADP will remain deenergized.

Withrelay ADP deenergize'd and relay HD now energized by current of normal polarity, lamp Y of upper group A of signal 4a, while a train occupies the first block in the rear of signal 4a, will remain lighted by the circuit previously traced for this lamp. Lamp G of lower group B of the lamps of signal 4a will now be lighted by a circuit passing from terminal I), through contact 63 of relay ER, back point of contact 65 of relay ADP, front point of contact 61 of relay HD, contact 69 of relay HD closed in the left-hand position, and lamp G of group B of signal 4a, to terminal 0.

When the first train clears the third block in advance of signal 4a, so that the first three blocks in advance of signal 4a are unoccupied, code following relay GP for signal M will again become energized by coded current of normal polarity, this time passing from terminal b, through the winding of relay ER for the next signal in advance of signal 40., contact 58 of coding device CT for the next signal in advance of signal 4a, contact 68 in the normal position and contact 60 closed at the front point, both of relay HD for the next signal in advance of signal 4a, contact 43 of relay a4TR, conductor 42, contact 4| of relay 4TR, winding of relay CP, contact 36 of relay 4TR, conductor 35, contact 34 of relay 0:4TR, and the front point of contact 6| of relay HD for the next signal in advance of signal 4a, to terminal 0. When a second train now occupies the first block in the rear of signal 4a, lamp G of group A of signal 4a and lamp R of group B of signal do will again become lighted as previously described.

Referring now to Fig. 3, a diagrammatic vievi is here shown of a modified form of the apparatus shown in Fig. 2 for controlling combined semaphore and color light signals in a three block automatic, signaling system. As shown in Fig. 3, each signal has an upper unit A including an upper quadrant semaphore arm 82 and a lamp 8i which, upon becoming lighted, shines through the green, yellow or red lens which is moved in front of lamp 8| when arm 82 moves to its 90, 45 or 0 position, respectively. Each signal has also a lower unit B which comprises a yellow lamp Y.

Whereas when light signals are used, as shown in Figs. 1a, 1b and 2, a slow release repeater such as relay ADP is desirable in order to prevent erroneous flashing of a red. indication under given conditions, the operation of semaphore signals is such that the slow release repeater relays are not needed for the control of semaphore signals, and therefore no ADP relay is shown in Fig. 3. The line circuit for controlling each relay HD is pole changed, in Fig. 3, by contacts H and 13 operated by the next signal in advance instead of by contacts of a relay ADP as in Fig. 2. Otherwise, the various parts of the apparatus shownin Fig. 3 for controlling each signal are controlled similarly to the corresponding parts shown in Fig. 2.

The indications displayed by each signal in a three block signal system of the type, such, for example, as signal 41) shown in Fig. 3, under various traflic conditions, and'the meanings of these indications are stated in the following table:

Indication displayed Meaning of indication Unit A Unit B Arm in O or horizontal First block ahead is position.

occupied. Arm in 45 ps1t1on.-.

First block ahead is clear, second block is occupied.

Arm in 45 position. Lamp Y of unit 0 First two blocks ahead lighted. clear, third block occupied. Armin90position First three blocks ahead are clear.

With three blocks clear in advance of signal 41), shown in Fig. 3, relay GP for signal 4b will be energized by coded current of normal polarity in a circuit a portion of which is shown adjacent signal 4b, and the rest of which is exactly similar to the portion shown adjacent ib for the relay CP for the next signal in the rear. The circuit by which relay GP for signal 4b is energized, with three blocks clear in advance of signal 4b, therefore passes from terminal I), through the winding of an approach lightingrelay ER. for the next signal in advance of signal 419, contact 58 of coding device CT for the next signal in advance, front point of contact Til of relay AD and back point of contact 60 of relay HD, both for the next signal in advance of signal 4b, contact H operated by the next signal in advance of signal 41), contact 43 of relay a4TR, conductor 42, contact M of relay 4TB, winding of relay CP, conductor 12, and. contact 13 operated by the next signal in advance of signal 411, to terminal 0.

Since this circuit is supplied with coded current of normalpolarity, contacts I! and 20 of'relay CP will close alternately in their left-hand and deenergized positions, following the code of the current which energizes relay CP. Secondary Winding I9 of transformer AT will therefore be energized, causing relay AD to be energized. With relay AD energized, the circuits for relay HD are open at contact 39 of relay AD.

Also, with relay AD energized, semaphore arm 82 of unit A of signal 417- will occupy the 90 position, under the control of circuits passing from terminal I), through front points of contacts 15 and 1! of relay AD, and the mechanism of signal 411 to terminal 0. With relay AD energized, the circuit for lamp Y of the lower unit B of signal 4b will be open at contact 18 of relay AD.

Whenever a train occupies the next block in the rear of signal 419-, lamp 8| of upper unit A of signal 4?) will be lighted by a circuit passing from terminal I], through contact 63 of relay ER, and lamp 8| to terminal 0.

Assuming now that a train passes signal 4b, causing relay 4TH to become deenergized, contact 4! or this relay will open the circuit for relay CP, causing relay GP to also be deenergized, and preventing relay I-ID from becoming energized. With relays AD and HD deenergized, the arm of signal 4b will move to the horizontal position, and lamp Y of unit 13 of signal 421 will remain unlighted.

When the'train clears the block of signal 4b and occupies the second block in advance of signal 4b, relay HD will become energized by steady current of reverse polarity passing from terminal b, through the winding of relay ER for the next signal in advance of signal 4b, a resistor 14, contact 13 operated by the next signal in advance, now closed in the lower position, conductor I2, winding of relay HD, contact 39 of relay AD, contact 4! of relay 4TR, conductor 42, contact 43 of relay a4TR, contact H operated by the next signal in advance of signal 413', now occupying its lower position, to terminal 0.

With relay HD energized by current of reverse polarity and relay AD deenergized, a circuit will be complete for causing the arm of signal 4b to move to the 45 position, this circuit passing from terminal b, through the back point of contact 15 of relay AD, contact I6 of relay HD, and the mechanism of signal 4b to terminal 0'. With relay HD energized by current of reverse polarity, contact 8!] of this relay will be open, and hence lamp Y of the lower unit B of signal 41) will remain unlighted.

It, now, the train moves into the third block in advance of signal 41), leaving the first two blocks unoccupied, relay ED for signal 4b will become energized by current of normal polarity passing from terminal I), through the winding of relay ER for the next signal in advance of signal 4b, a resistor i4, contact 68 of relay HD for the next signal in advance, closed in the right-hand position, front point of contact 60 of relay ED for the next signal in advance, contact ll operated by the next signal in advance, contact 43 of relay a iTR, conductor 42, contact 4| of relay 4TB, contact 39 of relay AD, winding of relay HD, conductor 12, and contact 13 of the next signal in advance, to terminal 0. Since the current supplied to this circuit is uncoded, relay CP will retain its contacts I! and 20 in the left-hand position, and hence secondary winding 19 of transformer AT will remain deenergized, leaving relay AD also deenergized.

With relay AD deenergized and with relay HD energized by current of normal polarity, the arm of signal 4b will be retained in the 45 position by the circuit previously traced. Lamp Y of lower unit B, when a train occupies the next block in the rear of signal 41), will now be lighted by a circuit passing from terminal I), through contact 63 of relay ER, contact 18 of relay AD, contacts 19 and 80 of relay HD, and lamp Y to terminal 0.

If the train now moves into the fourth block in advanceof signal 41), leaving the first three blocks in advance unoccupied, relay CP will become energized by coded current passing from terminal 17, through the winding of relay ER for the next sign-a1 in advance of signal 411, contact 58 operated by coding device CT for the next signal inadvance, contact 68 of the relay HD for the next signal in advance in the left-hand position, front point of contact 60 of relay ED for the next signal in advance, contact H operated by the next signal in advance, contact 43 of relay a lTR, conductor 42, contact 4| of relay 4TB, winding of relay CP, conductor 12, and contact 13 of the next signal in advance to terminal 0. With relay CP energized by coded current, relay AD will become energized, causing the arm of signal 4b to be operated to the 90 position by the circuits previously traced.

From the foregoing description and the accompanying drawings, it follows that in apparatus embodying my invention, I have provided means for controlling the signals in multiple block signaling systems todisplay a plurality of indications, by the use of constant and coded current of normal and reverse polarities and by coded current impulses of a given polarity alternated with coded current impulses of the opposite Apparatus embodying my invention also protects the signaling system from inductive interference and capacity feed from adjacent power lines.

It is to be understood that apparatus embodying my invention is not limited to the particular types of signals and signal aspects here shown, nor to three block and five block systems. It can also be used for four block signaling systems and for systems providing signal indications by each signal for more than five blocks.

Although I have herein shown and described only a few forms of railway signaling embodying my. invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into blocks, asignal for each of said blocks for governing traific movements into the associated block, a polarized code following relay for each of said signals, normal contacts of each of said relays closed in a normal position when the corresponding relay is energized by current of normal polarity and closed in a deenergized position when said relay is deenergized or is ener gized by current of reverse polarity, reverse contacts of each of said-relays closed in a reverse position when the corresponding relay is energized by current of reverse polarity and closed in a deenergized position when the relay is deenergized or is energized by current of normal polarity, a slow release normal decoding relay and a slow release reverse decoding relay for each of said code following relays, a normal decoding transformer for each of said normal decoding relays, a reverse decoding transformer for each of said reverse decoding relays, means controlled by normal and reverse polar contacts of each of said polarized code following relays for energizing the corresponding normal and reverse decoding transformers while said contacts are being operated in response to coded current, means controlled by each of said normal and reverse decoding transformers and by normal and reverse contacts respectively of the corresponding polarized code following relay for energizing the corresponding normal and reverse decoding relays respectively, a coding device for each of said signals, a pair of conductors for each of said signals across which the associated polarized code following relay is connected, a polarized signal con- '1 trol relay of the retained neutral contact type for each of said signals connected across the corresponding pair of conductors through back contacts of the associated normal and reverse decoding relays in series, traffic controlled means for each of said blocks, means controlled by the coding device for each signal and by the normal and reverse decoding relays and polarized signal control relay for the same signal and by the traffic controlled means for the next block in the rear for energizing the conductors for the next signal in the rear by steady current of normal or reverse polarity or by coded current of normal or reverse polarity or by code impulses of normal polarity alternately with code impulses of reverse polarity if said next block in the rear is unoccupied, and means controlled by the normal and reverse decoding relays and by the polarized signal control relay for each signal for operating the corresponding signal to display five different indications one for each of said five forms of current supplied to the conductors for directing traffic movements into the block and for operating the corresponding signal to display a stop indication if the block is occupied by a train.

2. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks for governing traffie' movements into the associated block, a pair of conductors for each of said signals, a polarized code following relay for each of said signals connected across the associated pair of conductors, a normal and a reverse decoding transformer for each of said code following relays, a normal and a reverse slow release decoding relay for each of said code following relays, means controlled by each of said code following relays for energizing the associated normal decoding relay through the associated normal decoding transformer when the corresponding code following relay is energized by coded current of normal polarity from its pair of conductors, means controlled by each of said code following relays for energizing the associated reverse decoding relay through the associated reverse decoding transformer when the corresponding code following relay is energized by coded current of reverse polarity from its pair of conductors, a polarized signal control relay of the retained neutral contact type for each of said signals connected across the associated pair of conductors through back contacts of the associated normal and reverse decoding relays in series, a coding device for each of said signals, means controlled by the coding device for each signal and by the normal and reverse decoding relays and polarized signal control relay for the same signal as well as by trafiic conditions in the next block in the rear for energizing the conductors for the next signal in the rear by steady or coded current of normal or reverse polarity or by code impulses of current of normal polarity alternately with code impulses of current of reverse polarity if said next block in the rear is unoccupied, and means controlled by the normal and reverse decoding relays and the polarized signal control relay for each signal for operating the corresponding sigfor each of said signals controlled by current of normal and reverse polarities in said conductors, a normal and a reverse decoding relay for each of said code following relays, means controlled by each of said code following relays for energizing the associated normal and reverse decoding relays when the code following relay is energized by coded current of normal and reverse polarities respectively, a polarized signal control relay for each of said signals controlled by steady current of normal and reverse polarities in the associated pair of conductors through back contacts of the associated normal and reverse decoding relays in series, a coding device for each of said signals, means controlled by the coding device for each of said signals and by the normal and reverse decoding relays and polarized signal control relay for the same signal as well as by traffic controlled means for the next block in the rear for energizing the conductors for the next block in the rear by steady or coded current of normal or reverse polarity or by impulses of coded current of normal polarity alternately with impulses of coded current of reverse polarity if the next block in the rear is unoccupied, and means controlled by the decoding relays and the polarized signal control relay for each signal for energizing the corresponding signal to display five different indications one for each of said five conditions of current for directing trafilc movements into its block if its block is unoccupied.

4. In combination, a stretch of railway track divided into blocks, a signal for each of, said blocks for governing traffic movements into the associated block, a pair of conductors for each of said blocks, a polarized code following relay for each of said signals controlled by current of normal and reverse polarities in said conductors,

\ a normal and a reverse decoding relay for each of said code following relays, means controlled by each of said code following relays for energizing the associated normal and reverse decoding relays when the code following relay is energized by coded current of normal and reverse polarities respectively, a polarized signal control relay for each of said signals controlled by steady current of normal and reverse polarities in the associated pair of conductors through back contacts of the associated normal and reverse decoding relays in series, means selectively controlled by traffic conditions on said stretch of railway track for energizing the conductors for each block by steady or coded current of normal or reverse polarity or by impulses of coded current of normal polarity alternately with impulses of coded current of reverse polarity, and means controlled by the decoding relays and the polarized signal control relay for each signal for operating the corresponding signal to display five different indications for directing traffic movements into the associated block.

5. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks, code responsive means for each of said signals selectively responsive to coded current of normal and reverse polarities, a normal and a reverse decoding device, means controlled by said code responsive means for operating said normal and reverse decoding devices when coded cure rents of normal and reverse polarities respectively energize said code responsive means, a polarized relay for each signal, means controlled by given trafiic conditions in advance of each signal and by the decoding devices for the same signal in the deenergized condition for energizing the polarized relay for that signal by current of normal or reverse polarity according as the first two blocks in advance of the signal are clear while the third block is occupied or thefirst block in advance is clear while the second block is occupied, means controlled by other given traffic conditions in advance of each signal for energizing the code responsive means for that signal by coded current of normal or reverse polarity or by impulses of coded current of normal polarity alternately with impulses of coded current of reverse polarity, and means controlled by the polarized relay and the normal and reverse decoding devices for each signal for operating the corresponding signal to display five different indications one for each of said five forms of current and to display a stop indication when said polarized relay and said decoding devices are deenergized.

6. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks, code responsive means for each of said signals selectively responsive to coded current of normal and reversepolarities, a polarized relay for each of said signals, means controlled by the code responsive means for each signal when energized by coded current for preventing energization of the polarized relay for the same signal, means controlled by given trafiic conditions in advance of each signal for energizing the code responsive means for the corresponding signal by coded current of normal or reverse polarity or by impulses of coded current of normal polarity alternately with impulses of coded current of reverses polarity, means controlled by other given traffic conditions in advance of each signal for energizingthe polarized relay for the same signal by steady current of normal or reverse polarity, and means controlled by the polarized relay and by the code responsive means for each signal for operating their signal to display a corresponding indication for each of said conditions of current for directing trafiic movements into the associated block and a stop indication when said polarized relay and code responsive means are deenergized.

7. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks, code responsive means for each of said signals selectively responsive to coded current of normal and reverse polarities, a normal and a reverse decoding device, means controlled by said code responsive means for operating said normal and reverse decoding devices when coded currents of normal and reverse polarities respectively energize said code responsive means, a polarized relay for each signal, means controlled by given tramc conditions in advance of each signal and by the decoding devices for the same signal in the deenergized condition for energizing the polarized relay for that signal by current of normal or reverse polarity according as the first two blocks in advance of the signal are clear while the third block is occupied or the first block in advance is clear while the second block is cupied, means controlled by other given traffic conditions in advance of each signal for energizing the code responsive means for that signal by coded current of normal or reverse polarity, and means controlled by the polarized relay and the normal and reverse decoding devices for each signal for operating the corresponding signal to display four difierent indications one for each of said four forms of current.

8. In combination, a stretch of railway track divided into blocks, a signal for each of saidolocks, code responsive means for each of said signals selectively responsive to coded current of normal and reverse polarities, a polarized relay for each of said signals, means controlled by the code responsive means for each signal when energized by coded current for preventing energization of the polarized relay for the same signal, means controlled by given traffic conditions in advance of each signal for energizing the code responsive means for the corresponding signal by coded current of normal or reverse polarity, means controlled by other given traflic conditions in advance of each signal for energizing the polarized relay for the same signal by steady current of normal or reverse polarity, and means controlled by the polarized relay and by the code responsive means for each signal for operating that signal to display a corresponding indication for each of said conditions of current for directing traffic movements into the associated block.

9. In combination, a stretch of railway track divided into blocks, a signal for each of said blocks, code responsive means for each of said signals selectively responsive to coded current for opening a given contact only when energized by coded current of a given polarity, a control relay for each of said signals, means controlled by a given trafiic condition in advance of each signal for energizing the code responsive means for the corresponding signal by coded current of said given polarity, means controlled by a second given traffic condition in advance of each signal for energizing the control relay for the corresponding signal only if the given contact for the code responsive means for the same signal is closed, and means controlled by the control relay and the code responsive means for each signal for controlling the corresponding signal to display a first or a second indication corresponding to said first and second given traffic conditions respectively.

10. In combination, a stretch of railway track, a signal for governing traific movements into said stretch, a signal control relay, a circuit for energizing said signal control relay under a given traffic condition on said stretch of track, code responsive means selectively responsive in a given manner to current of only a given polarity, means controllable by said code responsive means for opening said circuit for said signal control relay only when coded current of said given polarity energizes said code responsive means, means for energizing said code responsive means by coded current of said given polarity under a second given trafiic condition, and means controlled by said control relay and said code responsive means for controlling said signal to display a first or a second indication corresponding to said first and second given traffic conditions.

11. In combination, a stretch of railway track, a signal for governing traflic movements into said stretch, a signal control relay, code responsive means selectively responsive to coded current of a given polarity, a decoding relay, means controlled by said code responsive means for energizing said decoding relay only when coded current of said given polarity energizes said code responsive means, a circuit including a back contact of said decoding relay for energizing said signal control relay under a given trafiic condition on said stretch of track, a second circuit controlled by a second given trafiic condition on said stretch of track for energizing said code responsive means by coded current of said given polarity, a slow release repeater relay, a circuit including a front contact of said decoding relay for energizing said slow release repeater relay, and means controlled by said signal control relay and said slow release repeater relay for controlling said signal to display a first or a second indication when one or the other of said signal control and slow release repeater relays is energized and to display a stop indication when said signal control and slow release repeater relays are both deenergized.

12. In combination, a stretch of railway track, a signal for governing traific movements into said stretch, a polarized signal control relay, code responsive means selectively responsive to coded current of a given polarity, means controlled by a first and second given traffic condition on said stretch of track for energizing said polarized signal control relay by current of normal and reverse polarities respectively, means controlled by a third given trafiic condition on said stretch of track for energizing said code responsive means by coded current of said given polarity, means controllable by said code responsive means only when energized by coded current of said given polarity for preventing energization of said polarized signal control relay, and means controlled by said polarized signal control relay when energized by current of normal or reverse polarity and by said code responsive means when energized by coded current of said given polarity for controlling said signal to display a first or a second or a third indication respectively.

13. In combination, a stretch of railway track divided into a first and a second and a third section, a signal for governing trafiic movements into said stretch, a polarized signal control relay, code responsive means selectively responsive to coded current of a given polarity, a first and a second and a third traific responsive device controlled by traffic conditions in said first and second and third sections respectively, means controlled by said traffic responsive devices for energizing said polarized signal control relay by current of reverse or normal polarity according as said first section is unoccupied while said second section is occupied or said first and second sections are unoccupied while said third section is occupied, means controlled by said traffic responsive devices for energizing said code responsive means by coded current of said given polarity when all three sections are unoccupied, means controllable by said code responsive means only when energized by coded current of said given polarity for preventing energization of said polarized signal control relay, and means controlled by said polarized signal control relay when energized by current of normal or reverse polarity and by said code responsive means when energized by coded current of said given polarity for controlling said signal to display a first or a second or a third indication respectively.

RALPH R. KEMIMERER. 

